Turkey has fired hundreds of senior military staff serving at NATO in Europe and the United States following the failed July 15 coup, Hurriyet Daily News reports, citing documents seen by Reuters.

In a classified military dispatch, 149 military envoys posted to NATO centers in Germany, Belgium, the Netherlands and Britain were ordered on September 27 to return to Turkey within three days.

Most were dismissed from service on their arrival, arrested and jailed, according to a Turkish military official at NATO and two farewell letters sent by departing Turkish officials emailed to colleagues at NATO and seen by Reuters.

One of those letters wrote of a “witch hunt” of senior air force commanders serving overseas.

In total, about 400 military envoys have been fired so far, the Turkish military official said. Two non-Turkish NATO staff familiar with the situation confirmed that Turkish personnel are being recalled but did not have more details.

Turkish officials have said that the scale of the crackdown is justified by the gravity of events on July 15, when rogue soldiers commandeered tanks, fighter jets and helicopters, bombing parliament and government buildings in their attempt to seize power. More than 240 people, many of them civilians, were killed.

Turkey is a vital ally to the West in the war against Islamic State of Iraq and the Levant (ISIL) militants and in tackling Europe’s migrant crisis. It is also one of the main troop contributors to NATO’s training mission in Afghanistan.

Of the 50 military staff posted to the Turkish delegation at NATO’s headquarters in Brussels, only nine remain, according to the Turkish official who spoke to Reuters.

A NATO official said Turkey had notified the alliance about military personnel changes atNATO commands in Europe and in the United States, adding that the issue has been discussed at a senior level between NATO and Turkish officials.

“We are confident that Turkey will keep its commitment to the rule of law when bringing the perpetrators of the coup to justice,” the NATO official said.

Meanwhile, Turkey’s Defense Ministry has confirmed that it had dismissed over 230 military personnel for suspected links to the Gülenists on Oct. 11.

According to a ministry statement, from a total of 233 people fired, 201 were from Turkey’s air force and 32 from the navy.

Among this total, 158 commissioned officers, 67 sergeants and eight specialized sergeants were relieved of their duty.

Seven military judges and colonels were also removed, bringing the total number of dismissed officials to 3,939.